Explanation:
What are those unusual spherules on Mars?
The
Mars Opportunity rover
has now photographed several unusual nodules on Mars that
have a nearly spherical shape.
Many times these spherules are embedded in
larger rock outcroppings but appear grayer.
Pictured in the inset is one such spherule embedded in a rock dubbed Stone Mountain, visible to the
Opportunity rover now rolling
inside a small crater on
Meridiani Planum.
Opportunity was directed to go right up to
Stone Mountain to get a better look.
The inset picture spans only 3 centimetres across, revealing the rock to be named more for shape than actual size.
Scientists are currently debating the origin of the
spherules.
One leading hypothesis holds that the
beads were
once-molten rock that froze in mid-air after an
impact or a volcanic eruption.
Another hypothesis holds that the spherules are
concretions, hard rock that slowly accumulates around a central core.
Opportunity will work to solve this mystery and others over the next few days.